Observable behaviour

The externally visible outcome of a system action that a test can verify, as distinct from internal implementation details. In test automation, assertions should check observable behaviour rather than internal state: for example, checking that a specific error message appears on screen, or that a button becomes visible after a reset, rather than checking a variable value inside the code. AI-generated assertions sometimes check implementation details that are brittle or invisible to the user, so reviewing whether each assertion targets a genuine observable outcome is one of the key disciplines when reviewing AI-produced automation code.